Fritsch R, Bohle B, Vollmann U, Wiedermann U, Jahn-Schmid B, Krebitz M, Breiteneder H, Kraft D, Ebner C. Bet v 1, the major birch pollen allergen, and Mal d 1, the major apple allergen, cross-react at the level of allergen-specific T helper cells.
J Allergy Clin Immunol 1998;
102:679-86. [PMID:
9802379 DOI:
10.1016/s0091-6749(98)70287-8]
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Abstract
BACKGROUND
Food allergy to apple is frequent in individuals allergic to tree pollen. The major allergens of birch, Bet v 1, and apple, Mal d 1, have been cloned and sequenced and display a high degree of sequence identity, leading to IgE cross-reactivity.
OBJECTIVE
We sought to investigate cross-reactivity between Bet v 1 and Mal d 1 at the level of allergen-specific T lymphocytes.
METHODS
PBMCs of 13 patients allergic to birch pollen with oral allergy syndrome to apple were stimulated with rBet v 1 and rMal d 1, respectively, thereby establishing allergen-specific T-cell lines and T-cell clones. rMal d 1-specific T-cell cultures were tested for reactivity with rBet v 1, and rBet v 1-specific T cells were analyzed for reactivity with apple allergen. Cytokine production patterns in response to specific stimulation were evaluated. A selection of cross-reacting T-cell clones was mapped for epitope specificity by the use of overlapping Bet v 1- derived peptides.
RESULTS
Nineteen Mal d 1-specific T-cell clones were produced, 79% of which cross-reacted with Bet v 1. Eight of 18 Bet v 1-specific T-cell clones cross-reacted with Mal d 1. Six peptides representing cross-reactive T-cell epitopes could be identified. The respective fragments from birch and apple displayed approximately 50% amino acid identity. Seventy percent of the cross-reactive T-cell clones revealed a T(H2)-like cytokine production pattern.
CONCLUSION
The results indicate that cross-reactivity between apple and birch pollen leading to the clinical oral allergy syndrome occurs not only at the serologic, but also at the cellular level.
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